Ramus Franck, Rosen Stuart, Dakin Steven C, Day Brian L, Castellote Juan M, White Sarah, Frith Uta
Institute of Cognitive Neuroscience, University College London, London, UK.
Brain. 2003 Apr;126(Pt 4):841-65. doi: 10.1093/brain/awg076.
A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: (i) the phonological theory, (ii) the magnocellular (auditory and visual) theory and (iii) the cerebellar theory. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, four from a motor deficit and two from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as demonstrated by five of the dyslexics. Auditory disorders, when present, aggravate the phonological deficit, hence the literacy impairment. However, auditory deficits cannot be characterized simply as rapid auditory processing problems, as would be predicted by the magnocellular theory. Nor are they restricted to speech. Contrary to the cerebellar theory, we find little support for the notion that motor impairments, when found, have a cerebellar origin or reflect an automaticity deficit. Overall, the present data support the phonological theory of dyslexia, while acknowledging the presence of additional sensory and motor disorders in certain individuals.
为了评估发育性阅读障碍的三种主要理论，开展了一项多案例研究：（i）语音理论，（ii）大细胞（听觉和视觉）理论，以及（iii）小脑理论。对16名患有阅读障碍的大学生和16名对照大学生进行了一系列完整的心理测量、语音、听觉、视觉和小脑测试。个体数据显示，所有16名阅读障碍者都存在语音缺陷，10名存在听觉缺陷，4名存在运动缺陷，2名存在视觉大细胞缺陷。结果表明，语音缺陷可能在没有任何其他感觉或运动障碍的情况下出现，并且足以导致读写能力受损，5名阅读障碍者的情况证明了这一点。听觉障碍一旦出现，会加重语音缺陷，进而导致读写能力受损。然而，听觉缺陷不能简单地被描述为快速听觉处理问题，这与大细胞理论的预测不同。它们也不限于言语。与小脑理论相反，我们几乎没有找到证据支持以下观点：运动障碍一旦出现，其起源于小脑或反映自动性缺陷。总体而言，目前的数据支持阅读障碍的语音理论，同时承认某些个体存在额外的感觉和运动障碍。
